Impact of composite gelators on physicochemical properties of oleogels and astaxanthin delivery of oleogel-based nanoemulsions

In this study, binary systems of carnauba wax (CW) and 1-docosanol (DS) were first explored to enhance the properties of oleogels. Compared to the corresponding single component oleogels (0:5 and 5:0), a synergistic effect of oleogel strength was observed at CW:DS ratios of 1:4 (C1D4). At this ratio, the formed oleogel showed the highest hardness, rheological property and oil binding ability. Meanwhile, the gel-sol melting temperature of this oleogel at this ratio was lower than most of others. Subsequently, the effect of composite gelators on the astaxanthin delivery of oleogel-based nanoemulsion was explored. The oleogels at CW:DS ratios of 1:4, 0:5 and 5:0 were chosen to prepare oleogel-based nanoemulsions. The oleogel-based nanoemulsion formulated with C1D4 had the largest droplet size. In vitro digestion study revealed that although C1D4 oleogel-based nanoemulsion could not improve the extent of lipolysis, it could significantly improve astaxanthin bioaccessibility when compared with the other two oleogel-based nanoemulsions. This study developed a new formula of oleogel-based nanoemulsion with improved astaxanthin bioaccessibility. This novel formulation approach might also be suitable for other hydrophobic nutraceuticals and provided a new idea for the preparation of oleogel-based nanoemulsions with improved nutraceutical bioaccessibility.